If you want or have to use electricity on your own, you face this dilemma: Electricity will make your life richer, but electricity is energy -like fire- and therefore dangerous. Electrical safety can be achieved following simple rules, but you can not bend these, never.

Steps

Part 1

Protecting Yourself

1

Be very aware of the risks. Electricity is energy -like fire- but is invisible, odourless and when you touch it, you have made a mistake. If you want to make or amend any electrical construction you must protect against:

1. electrocution, the 'electrical shock',

2. inflammation, combustion or smoke and gas generation

3. cost ineffectiveness

2

Use insulation to prevent electrocution. Electric energy is tied to metal, always to two separate pieces, called 'poles'. Electrocution will happen, if electricity finds a way from one pole to the other through a biological entity, e.g. you. You can prevent this with insulation. These are materials which do not conduct electricity. Unfortunately water does, which makes the task much more difficult, because one can not use spongy materials, which may harbour water. The material of choice is 'plastic', which nearly always is waterproof. Your best friend in your own constructions will be 'silicon', which can applied around any metal, will harden to a rubbery consistency, and will make the metal beneath safe against contact and water.

3

Use the right wire to prevent inflammation. Electric energy needs strands of metal to go from one pole to another, 'wires'. This is called 'current'. Unfortunately it leaves a fraction of energy in the wire itself. This will heat up the wire, and lead sometimes to a vicious circle, because warmer wire will use a bigger fraction of the current, which makes the wire even hotter, until all energy is consumed by the wire. This will cause the wire become so hot it may melt and burn anything around it -the insulation- to a crisp and produce a lot of smoke and sometimes poisonous gas.

You can prevent this happen only by using the right size of wire, because luckily double size wire means half amount of heat, until all heat will be absorbed in the surrounding of a wire.

The most critical part of installation is making a connection between two ore more wires. Here the loss of current problem described above is aggravated by so called 'oxidation'. Oxidized contacts will pick up even greater amounts of current and conversion into heat, which will cause more oxidation and the predictable catastrophic outcome.

You can prevent this happen by driving out all air by replacing it with solder material, in principle soldering wires together. This has drawbacks, so often just the stranded wire ends are soaked with solder ,'tinning'. Your best friend in your own constructions will be a measuring instrument called 'multimeter' which can tell you the amount of energy lost in a wire.

4

Plan for the costs. As much as you will like electricity in modern life, is does not come cheap. Although somebody on a 'electrical grid' will only pay very little for useful amount of energy, this is only possible by a massive investment over generations and the political protection for the energy merchants, with well documented results. On your own you have to calculate precisely the balance of investment and desired consumption to come to a satisfactory solution.

Part 2

Preparing

1

Make sure you have the right tools. Necessary tools not found usually in a handyman’s box are wire cutter and wire stripper, fully insulated screwdrivers, a multimeter and a soldering station with solder. You have to add one new pair of probe wires with 2.5mm² and one very long probe wire 0.2mm² with a clamp additional to the multimeter probes, which come with the purchase. This modification will enable you to make measurements crucial to avoid the fire hazard from electric wires.

2

Buy the materials for safe electricity production.

To avoid the contact hazard, the number one priority is that you need switch-boxes, trunking or ducting materials, insulation materials like tape and neutral silicon.

To avoid the fire hazard, you need wires in different diameters and preferably different colours, connection bars, fuses, switches and watchdog devices.

Only if you can avoid the above hazards should you worry about economy and affordability. Put your safety above your wallet, and don't attempt the project if you can't get safe materials.

Part 3

Setting Up an Installation (Solar Example)

1

Look for your connectors first. Most solar panels will come with two wires with special connectors. Let's assume type MC4. You have to make sure you get extra connectors with your purchase of your panels. Connect these to wires in the length to your first switch-box. This has to be weatherproof.

2

Know your maximum current. There is a label on the panel, which will say, how much current it will give in favourable conditions. Lets assume 8A ('Ampere').

3

Choose the right wire dimension. This maximum current has to go safely into your first breaker box 2m away near the mount. What diameter of wire will you need? Page 16 of these guidelines shows a table with diameter vs. current content. The answer is deceptive: Although a 1.5 mm² wire will be able to withstand 18.5A, but a safe connection into your first breaker switch needs at least a 2.5mm² wire.

4

Get a weatherproof box for your system. It may look like a unnecessary expense, but if something goes wrong, you will have a crucial measuring point and the chance of disconnecting your solar panels completely. Mind you, the panel will try to give current, as soon it is illuminated.

5

Use a big enough diameter for the wire into your batteries. This is much longer and needs more attention for heat dissipation. Let's assume you have 2 panels of 8A = 16A to send into your batteries. These are 10m away from your first breaker box, into your first breaker box 2m away near the mount. What diameter of wire will you need? Page 21 of above document shows a table with permissible current vs. length.

Your wires are in a irrigation tube to protect from solar radiation, but it will get rather hot in this tube. The answer is 28m of 2x2.5mm² will withstand 27A, but page 17 shows a table of temperature vs. permissible load.

So at 45C you can use only 66% of that 27A, and the wire will be at 60C. Every meter more in length will push the specification to the limit, so you use 2x4mm² or 4x2.5mm². You will be able to measure the actual loss of power in that wire.

6

Put the cover on. Measurements are still possible with probes onto the fixing screws.

7

Consider the connection from the batteries into the inverter. The current there depends on the power converted and the voltage of the battery. 100A is a typical value. You will see, your inverter comes with a very thick cable, with the terminals tightly fixed. Your job here is to make a matching counter piece, so you can put screws through the eyes of the terminals. Maybe you need help from a metal workshop. If there is one battery stack, every single wire has to withstand the current, so every connection has to be oxidation free and has to be maintained to stay free.

8

Set up the wire from the inverter into your house breaker box. These carry 16A, the length is 2m, so 2.5mm² is sufficient at 35C.

Community Q&A

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Tips

The calculations for wire dimensions are very well documented in above mentioned pdf. Well, it's in German. It is not certain who is more offended when you state, the Germans are the last to tolerate mistakes in their documentations. Of course there must be a analogous document in your language.

Warnings

wikiHow does not have any responsibility for the accuracy or usability of an article. Any claims for damage to persons, property real or intellectual are frivolous and futile.

Most expressions in 'apostrophes' are popular names, which you will be able to communicate in a builders market. In technical literature there are more exacting and comprehensive terms.